In certain disease states, the heart lacks sufficient pumping capacity to meet the needs of the body. This inadequacy can be alleviated by providing a mechanical pumping device referred to as a ventricular assist device (“VAD”) to supplement the pumping action of the heart. Considerable effort has been devoted to providing a VAD which can be implanted and which can remain in operation for months or years to keep the patient alive while the heart heals (bridge-to-recovery), or which can remain in operation permanently (destination therapy) or until a suitable donor heart becomes available if the heart does not heal (bridge-to-transplantation).
The VAD is typically connected to the heart, most commonly to the left ventricle, which is responsible for pumping oxygenated blood through the aortic valve to the general body. For example, a VAD may include a pump which is installed in the body outside of the heart. The VAD may have an inlet cannula connected to the interior of the left ventricle and connected to the intake of the pump. The VAD may also include an outlet tube connected to the outlet of the pump, routed along the outside of the heart, and grafted to the aorta. Installation of a VAD, particularly a VAD that makes use of an outflow graft, often requires cardioplegia and/or a cardiopulmonary bypass (“CPB”). Cardioplegia and CPB can extend the time of the implantation procedure and has risks which can be significant.
As disclosed in commonly owned U.S. Publication No. 2009/0203957, the disclosure of which is hereby incorporated by reference herein, one solution developed to avoid the need for an outflow graft is a pump that is implantable within the left ventricle, which can pump blood disposed within the left ventricle directly through the aortic valve via an outflow cannula coupled to an outlet of the pump. Installation of such a device is typically performed by inserting the outflow cannula and pump through a cored opening in the apex of the heart. This device avoids the need for connecting an outflow cannula external to the heart, and greatly simplifies the installation procedure.
Despite the considerable efforts devoted to improvements in VADs, still further improvement would be desirable.